Switch actuating mechanism



June 2, 1953 J. w. DlCKEY 2,640,899

SWITCH ACTUATING MECHANISM Filed July 17, 1950 Z3 O 7 5 6147a e I zz a1 a 5 7 6J 7 5 I 41*1517342? 7 1'0 39 as T amass.- John ATTORNEY Patented June 2, 1953 SWITCH ACTUATING MECHANISM John W. Dickey, Newfield, N. Y., assignor to Bendix Aviation Corporation, a corporation of Delaware Application July 17, 1950, Serial No. 174,245

4 Claims.

The present invention relates to switch actuating mechanism and more particularly to means for controlling an electrical switch. in accordance with the rotation of an engine-driven element. The switch may be used to open a circuit such as the ignition circuit or an electrical fuel pump circuit when the engine stops, in order to reduce fire hazard; or it may be adapted to close a control circuit to cause actuation of the starting mechanism in case of engine stall.

This application is a continuation in part of applicants prior co-pending application Ser. No. 96,347 filed May 31, 1949.

It is an object of the present invention to provide a switch responsive to a running function of an internal combustion engine, for controlling auxiliary apparatus such as a fuel pump or the electrical starting system for the engine, and incorporating an improved form of coupling connection to a rotating part of the engine or of a device driven by the engine.

It is another object to provide such a device having a combined viscous and frictional slip connection for actuating the switch which is mechanically strong and rigid, and which is arranged to rapidly dissipate any heat developed by slippage of the frictional connection.

It is another object to provide such a device in which the viscous coupling is connected directly to the engine driven part and the slip connection is located between the viscous coupling and the switch actuating element.

It is another object to provide such a device in which the slip connection includes a spring ring embracing its driving member and arranged to unwrap and reduce its pressure on the driving member responsive to torque transmitted therethrough Further objects and advantages may be apparent from the following description taken in connection with the accompanying drawing in which:

Fig. l is an elevation of a preferred form of the invention, partly broken away and in section, the elements of the electrical system being shown diagrammatically;

Fig. 2 is a section taken substantially on the line 2'-2 of Fig. 1; and

Fig. 3 is a section on an enlarged scale taken substantially on the line 33 of Fig. 1.

In Fig. 1 of the drawing there is illustrated a portion of a generator frame I, the shaft 2 of which is arranged to be driven by an internal combustion engine, not illustrated, in a conventional manner. A driving shaft 3 for the switch operating mechanism is rigidly mounted in any suitable manner in an axial opening 4 in the end of the generator shaft 2, and a driving disc 5 is fixed on the end of the driving shaft 3 so as to rotate therewith.

A coupling member 6 is journalled on the shaft 3 and has a chamber 1 formed in one end thereof enclosing the driving disc 5. The chamber 1 is filled with a slow flowing viscous material 8, preferably a silicone jelly or putty, the viscosity of which varies slightly throughout a wide range of temperature change. The chamber 1 is closed by an elastic diaphragm 9 retained by a cap I I suitably fixed on the end of the coupling member 6, whereby the viscous material 8 is retained in the chamber 1 and provides a connection between the driving disc 5 and the coupling member 6, which is substantially rigid as respects sudden impulses transmitted by the driving shaft 3, but which will slowly yield and permit relative rotation responsive to sustained torque.

In order to prevent escape of the viscous material along the bearing of the coupling member 6 on the shaft 3, the driving disc 5 and coupling member are formed with flat radial surfaces forming a thrust bearing as indicated at l0, and a spring Ill is provided for maintaining these surfaces in engagement with each other.

The coupling member is provided with a peripheral seat or recess I2 for the reception of a.

channeled or grooved ring of a wear-resisting material such as nylon. or the like, fixedly mounted thereon in any suitable manner.

A spring ring member I4 is seated in the channel of the nylon ring l3, closely embracing the same, and is provided with an out-turned arm [5 adapted to engage a. spindle l6 which actuates a switch indicated generally by numeral IT.

The spring ring [4 is wrapped around the coupling member 6 in such a. direction that when the driving shaft 3 is rotated in the direction of the arrow (a), it unwraps and releases its pressure on the nylon ring [3 in response to the torque transmitted through the frictional c0nnection formed thereby.

In the present instance the switch I! is used to control the starting mechanism for the internal combustion engine in such manner as to cause the starting mechanism to. operate whenever the ignition switch is closed while the engine is stationary, similar to the system illustrated in Fig. 4 of applicants copending application above cited.

The starting system comprises a battery 18 grounded at 18 and connected by a lead 21 to an electromagnetic starting switch 22 controlling the starting motor which is grounded at 23 to complete the starting circuit. A lead 24 connected to the battery lead 2! is provided with a manual switch 25 for controlling the ignition circuit of the engine, and manual switch 25 is con nected to one end of the solenoid 25 which actuates the magnetic starting switch 22. The opposite end of coil 26 is connected by lead 21 to one terminal 28 of switch H, the other terminal 3 29 of which is connected by lead 3| to the generator G, which is grounded at Terminals 28, 29 or" switch ll are bridged by a resistor 33 having a value such as to pass just sufiicient current to prevent the starting switch 22 from opening after it has been closed.

Switch ll is provided with a bridging contact 34 arranged to connect the terminals 28, 29 when spindle it is in its normal position as determined by a spring 35. This spring connects the spindle to a casing which encloses the switch actuating mechanism and is attached as indicated at 31 to the generator frame 1. The spindle I6 is fulcrumed on a flexible diaphragm 38 which is sealed in an opening in casing 35 by means of a switch housing suitably attached to the casing 36 as tion coupling E l.

In operation, starting with the parts in idle position, closure of the manual switch 25 causes energiaation of the starting switch coil 26 since the v. tch .5? is closed by the spring 35. This causes closure of the starting switch 2'2 and consequent actuation of the starting motor to crank the engine, Rotation of the generator shaft 2 by the is transmitted through the viscous and friction couplings so as to apply torque to the spring 55 which swings the switch spindle Hi against action of spring 35 and opens switch 57. st a switch 2.2 however, is held closed by the current ,versing the resistor 33 since the i-oltage of th ge erator when rotated cranking speed i l ihen the engine starts, the voltage of the generator bui ds up ano prevents passage of cur,- rent through the coil thus causing the starting switch 22 to open and deenergize the starting circuit.

Thereafter. actuation of the starting system is prevented as long as the engine is rotating by reason of the opened condition of switch. S1. Fhen the stops for any reason, the viscous coupling yields slowly, permitting the spring 35 to move the spindle 15 so as to cause closure of the m h I? after a suitable time delay so as to permit the engine to come ,completely to rest. If the ignition switch 25 is then closed, the starting operation is repeated as above set forth.

Although but. one embodimentof the invention has been shouh and described, it will be understood that various changes may be made in the design. and arrangement of the parts without departing from the spirit of the invention.

I claim:

1. In combination with a rotary member and a switch to be actuated thereby, a driving shaft connected to rotate with said member having a driving disc fixed thereon; a coupling member journalled on the driving shaft having a chamber enclosing said disc, 2. slow-flowing material in said chamber forming a viscous connection from the disc to the coupling member rotating the coupling member substantially in unison with the disc, s ring member embracing the coupling member mounted for limited arcuate movement and having a friction connection therewith; means connecting the spring member to the switch for actuating the switch responsive torotation of the coupling member, and elastic means for returning the spring member to idle position, through yielding of the viscous connection, a predetermined time after the driving shaft stops rotating; in which said chamber is substantially filled with the viscous material, and including further an elastic closure for said chamber sealing it against escape of the viscous material while permitting expansion and contraction thereof.

2. In combination with a rotary member and a switch to be actuated ther by, a driving shaft connected to rotate with said member having a driving disc fixed thereon; coupling member journalled on the driving shaft having a chamber enclosing said disc, a slow-flowing material in said chamber forming a viscous connection from the disc to the coupling member rotating the coupling men ber substan y in unison with the disc, a sprin member tracing the coupling member mounted for limited arcuate movement and having a friction connection therewith; means connecting the spring member to the switch for actu. .5; the switch responsive to rotation of the coup 1g member, and elastic means for ret member to idle position, through yielding 0f the viscous connection, a predetermined time after the driving shaft stops rotating; in which the driving shaft is rigidly mounted. on the rotary member coaxially therewith and including further means for preventing longitudinal movement of the coupling member on said shaft.

3. The combination set forth in claim 2 in which the coupling member provided with a flat bearing surface cooperating with a corresponding surface on the side of the driving disc; and including turther, spring means compressing said surfaces t "ether to prevent escape of the viscous material ween said surfaces.

In combination. a rotatable element, on electrical switch, means for actuating the switch rcsponsive to rotation of the element including a drive shaft rigidly mounted on the rotatable element coaxially therewith, driving disc fixed on said shaft, a coupling member journalled on the shaft having a circular recess loosely housing the disc, a semi-solid material in the recess forming a viscous connection between the and coupling member, said coupling member having a circular peripheral channel, and a spring ring memberseated in said channel forming a friction connection therewith and having a radially extending arm, said switch having an actuating lever positioned to be engaged and operated by the spring arm, and elastic means limiting the arcuate movement of the ring member, and operative to return the ring member to idle position, through yielding of the viscous connection, a predetermined time after the drive shaft stops rotating; in which one of the rubbing surfaces of the frictional connection is formed of nylon.

JOHN W. DICKEY.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Country Date Sweden Feb. 22, 1939 Great Britain Sept. 3, 1925 Number Number 

